1. Field of the Invention
The present invention relates to a disk cartridge used as a container for a disk-like recording medium. More particularly, the present invention relates to an improvement in a lining member attached to the inner surface of the casing of the disk cartridge.
2. Discussion of Background
A floppy disk has widely been used as an exchangeable information storage medium which can be fitted to a magnetically recording and reproducing device and can be removed from it for storage or transportation in the same manner as a magnetic tape cassette and a disk pack. 8-inch and 5-inch floppy disks have been commonly used. For such floppy disks, a thin flexible jacket made of vinyl chloride is used as a casing to protect a magnetic disk. However, the mechanical strength of the jacket is too weak to provide sufficient protection to the magnetic disk. Further, since the jacket has windows to allow insertion of a magnetic head and to drive a magnetic disk, careful attention to prevent dust from being deposited thereon is needed in consideration of eliminating such drawback. 3.5-inch floppy disks have employed a construction as follows. Thick, hardly deformable, strong upper and lower half casings are combined to form a hard casing; a shutter is provided at a window to allow the insertion of a magnetic head, and a hub formed on a magnetic disk is placed to face the window for driving the magnetic disk so that the disk is held in the hard casing in a rotatable manner.
A lining member for effecting cleaning function to remove dust from the surface of the inner wall of each of the half casings is attached to the inner surface of the half casings so that the lining members are in contact with the magnetic disk held in the hard casing. The lining member generally has a single structure and is composed of a non-woven cloth of excellent smoothness and which is difficult to be charged. Also known is a lining member having a three-layered structure.
However, the lining member of a single structure has a low dust retaining function, so that dust or fine particles are apt to be deposited on the magnetic disk to thereby cause errors in recording or reproducing. In an attempt of improving the cleaning function, a frictional force of the lining member to the magnetic disk becomes large, whereby other problems of increase in torque and damage to a surface of the magnetic disk may take place.
In the lining member having a three-layered structure which allows use of both surfaces, a relatively large amount of a binder (an adhesive) has to be contained in the middle layer to thereby prevent fibers in the nonwoven cloth from being deposited on the disk. The later case still has the same problem as the former case.